What are common pitfalls when handling checkbox submissions in PHP forms?

One common pitfall when handling checkbox submissions in PHP forms is not checking if the checkbox is checked before trying to access its value. This can lead to errors if the checkbox is not selected, resulting in undefined index notices or unexpected behavior. To solve this, you should use the isset() function to check if the checkbox is set before accessing its value.

// Check if the checkbox is set before accessing its value
if(isset($_POST['checkbox_name'])) {
    $checkbox_value = $_POST['checkbox_name'];
    // Process the checkbox value here
} else {
    // Checkbox is not checked
}